1. Field of the Invention
The present invention relates to a combined gas/steam turbine power station plant as defined by the preamble of claim 1. It also relates to a method of operating such a combined plant.
2. Discussion of Background
The term "combined gas/steam turbine power station plant" --abbreviated to combined plant below--is always understood as meaning the interaction of a gas turbine group with at least one steam turbine circuit, the exhaust gases from operation of the gas turbine group being passed through a waste heat steam generator (=waste heat boiler) in which the residual heat potential of said exhaust gases is used to generate the steam needed to act on the steam turbine. This additional steam generating capacity results in a higher thermal efficiency of the plant. Said combined plants therefore have a very good conversion efficiency which is in the order of magnitude of over 50%. Because, however, there is a discrepancy between the two types of engine (gas turbine group/steam turbine circuit) in relation to the respective start capability in terms of time, a delay may occur on starting in relation to the availability of the entire combined plant. A further bottleneck may arise in the start-up process if, in particular, no large electrical power is available for this purpose.